The present invention relates to mineral mining installations and more particularly to apparatus for controlling the position of a mineral mining machine movable along guide means.
One form of known apparatus, described in German patent specification No. 2319910 uses hydraulic piston and cylinder units connected between the guide means and elongate jib beams which are capable of pivoting in relation to the guide means and which are connected to roof support frames or structures.
In the construction described, the guide means takes the form of a scraper-chain conveyor having a guide for a machine in the form of a plough on its mineral-face side and the units are attached to the goaf side of the conveyor. The units can be extended or retracted to tilt the conveyor and hence the guide to thereby control the cutting level of the plough. There is a direct relationship between the working stroke or movement of the units and the angle of tilt thereby providing accurate control of the position of the plough. The conveyor and its guide are tilted about pivot axes between the beams and the conveyor and the beams extend by a sufficient distance outwardly from the conveyor to support the conveyor and the guide and inhibit any tendency to tilt due to the forces exerted by the plough. The beams can also serve to guide the floor sills of the support frames when these are shifted up to follow the working progress in known manner. Each adjusting unit is associated with two parallel beams which locate in guides of the associated support frame. At their forward ends, adjacent the conveyor, these beams are interconnected by a transverse yoke and the unit associated therewith is coupled to this yoke with a pivot pin with a horizontal axis. The yoke is itself pivotably connected to a coupling piece which defines the horizontal pivot axis between the conveyor and the beams and this coupling piece is in turn pivotably connected to the conveyor with a vertical pivot axis.
A general object of the present invention is to provide an improved form of apparatus.